The Braking System

Type and choice.
Fitting the pedal box and MS
Making, routing and securing brake pipes.

Rear Brake pipe routing

The ford master cylinder normally has 3 outlets, one for each of the front wheels and a shared single feed to the back wheels.

The brake pipes are normally routed down the drivers side sill area inside the bodywork but outside the cockpit area, this needs to be done before the bodywork is fitted.
At the rear of the car the pipe needs to be split using a t-piece to then feed each wheel. The rear swing arms will have an existing brake pipe fitted to them to allow the copper pipe to be secured to them. At each end will be a flexi-pipe. A short ford pipe is fitted at the caliper end and a longer pipe, available from Pilgrim is fitted to the inboard end. This pipe is secured to a pair of small brackets that are part of the chassis with locknuts.

Below are some pictures of the pipework.

Pipe work running down sill and then being split. Its best to put this somewhere you can get to it easily. (this is a left hand drive car and so the brake pipe runs down the passenger side)

rearbpipes1.JPG

The rear swing arm with flexi-pipes attached.

rearbpipes.JPG

The rear brakes in place.

rearbpipes2.JPG

Calipers
Handbrake

Bedding in and bleeding

Front Brake Upgrade

If you are using a Sierra as a donor car, an easy way to upgrade your brakes from the normal 240mm dia vented type is to use RWD Sierra Cosworth disks, with Scorpio 24V calipers and carrier brackets. The Scorpio calipers were designed for a 278mm disk, whereas the RWD Sierra Cosworth uses a 283mm disk. In order to fit the calipers, you will need to grind or file a small amount from the section of the caliper carrier bracket in order to allow clearance round the outside diameter of the Cosworth disk. The only other mod is to put a washer between the standard Sierra upright and the caliper carrier, when mounting the caliper carrier. This will help to centre the disk between the caliper carrier.

The standard Sierra hydraulic hoses fit straight on to the Scorpio 24V calipers, but whilst it is all apart, an upgrade to braided hoses is always a good idea.

Brake Performance

One thing to consider is the performance of the brakes on your Sumo. With larger diameter wheels and tyres, the rolling radius increases, which decreases the leverage available from the brakes. This is offset somewhat by the lower weight of the Sumo, which means standard Sierra brakes are adequate for general driving but are left wating when it comes to track days.

There are many off-the-shelf brake upgrades available for a Sierra to help improve the braking system, e.g. Wilwood, Hi-Spec, AP Racing, and more. One word of warning though, not all brake upgrades are alike. For instance, Wilwood and Hi-Spec both sell a 300mm 4-pot brake kit, which on face value look the same. However, the Hi-Spec calipers have 38.6mm pistons and the Wilwood's 1.75" (44.5mm) pistons. This is significant as the larger pistons result in more pressure on the pads and better brakes. The downside is more pedal tavel, although not too excessive. I'm not saying Hi-Spec kits are poor, from my experience their calipers flex less and don't squeal unlike the Wilwood kit, my point is choose your brake upgrade carefully and know what you are buying or you may not get the result you are expecting. There are also kits that will simply supply a bigger disc along with a bracket to move the standard Sierra caliper out to match.

Effect of Rolling Radius

Your Sierra donor might have 195/60-14 tyres with 260mm discs, but you are fitting 215/45-17 tyres on your Sumo. The increased rolling radius results in a 6% decrease in brake performance, but as I said above, the Sumo is lighter.

Effect of Piston Size

A standard non-ABS Sierra has 53.9mm pistons in sliding calipers and the Hi-Spec 300mm kit 38.6mm pistons in a fixed 4-pot caliper. The Hi-Spec caliper gives a 2.5% increase in pressure on the pad. This coupled with a larger disc gives a noticable improvement in braking.

If I get time I'll post a spreadsheet that does the calculations for you.

Rear Brakes

Rear discs were fitted on ABS equiped Sierra's and Granada's. If you choose to fit rear discs, keep in mind the fact that ABS equiped cars had 59.9mm diameter pistons in the front calipers. If you use non-ABS front calipers you will only have 53.9mm pistons, which will negatively affect the brake balance possibly causing an IVA failure. Therefore, either use ABS front calipers or choose a front brake upgrade that will give an increased piston area, examples could be Cosworth 4-pot calipers, Hi-Spec Billet-4 kit with 41.2mm pistons, Hi-Spec Monster-6 kit, Rally Designs Wilwood 300mm kit or Capri Sports BMW E38 4-pot kit.

Brake Servo

The donor vehicle servo and master cylinder area fitted as per the picture below.

brakeservo.jpg

Also a close up showing the back of the servo in contact with the chassis, the servo has a buldge to allow it to fit nicely.

brakeservo2.jpg

Note, if fitting one of the GM LS-series engines with individual coil packs on the rocker cover, you will need to move the brake servo over by 10mm to provide clearance. This is not a standard engine offered by Pilgrim but I thought I'd add this note in case anyone's considering this engine option. They really are superb engines, great value for money, pass emissions tests easily and are lighter than a normal SBC. If I get time I'll add a complete section on fitting an LS engine, or look out for the feature in Kit Car magazine detailing the build.

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